Has that been a factor?

这是一个因素吗？

Or had that been her idea of an impressive end to the test?

要不然她这样做就是为了给考试来一个令人印象深刻的结束？

The air tank and acetic tank that been used has the potential of explosion.

所使用的氧气瓶、乙炔瓶有爆炸危险。